Hi.
you can add Get Button for each button that you want to be able to break the easing inside the state that has the easing
if its only 1 button, use Bool Test and enable every frame and check the result of the Get Button.
if multiple buttons you can use Bool Any True for example.
Add transitions for 'Increase speed' / 'Decrease speed' for example which will be triggered when a button is 'true'
if you need a short delay for buttons to listen, then its best to make a separate fsm (call it 'ease button checker' for example.)
in the ease state, send an event (Start Listen) to the 'ease button checker' fsm.
and when going to a different state send an event (stop Listen)
on the 'ease button checker' fsm, set the 2 transition events as Global so they can be triggered any time.
on start listen state 1 use a Wait, then to the same thing with buttons but on the next state connected, send a event to the 'ease' fsm
Here is a video on global events in case you have no experience with this yet